Over the weekend Samsung silently updated their 840 EVO Performance Restoration Tool. The incremental update improved support for some system configurations that were previously not recognizing an installed 840 EVO. Samsung also improved how the GUI progress bar responds during the update process, presumably to correct the near silent failure that occurred when the tool was unable to update the drive's firmware. Previously, the tool would halt at 15% without any clear indication that the firmware could not be updated (this would occur if the tool was unable to issue the necessary commands to the SSD, mainly due to the motherboard being in the wrong storage controller mode or using an incompatible storage driver).

Still no word on relief for those owners of the original 840 (non EVO or Pro). We've also heard from some users with Samsung OEM TLC-based SSDs that showed the same type of slow down (some variants of the PM851 apparently used TLC flash). More to follow there.

Introduction

** Edit **

The tool is now available for download from Samsung here. Another note is that they intend to release an ISO / DOS version of the tool at the end of the month (for Lunix and Mac users). We assume this would be a file system agnostic version of the tool, which would either update all flash or wipe the drive. We suspect it would be the former.

** End edit **

As some of you may have been tracking, there was an issue with Samsung 840 EVO SSDs where ‘stale’ data (data which had not been touched for some period of time after writing it) saw slower read speeds as time since written extended beyond a period of weeks or months. The rough effect was that the read speed of old data would begin to slow roughly one month after written, and after a few more months would eventually reach a speed of ~50-100 MB/sec, varying slightly with room temperature. Speeds would plateau at this low figure, and more importantly, even at this slow speed, no users reported lost data while this effect was taking place.

An example of file read speeds slowing relative to file age.

Since we first published on this, we have been coordinating with Samsung to learn the root causes of this issue, how they will be fixed, and we have most recently been testing a pre-release version of the fix for this issue. First let's look at the newest statement from Samsung:

Because of an error in the flash management software algorithm in the 840 EVO, a drop in performance occurs on data stored for a long period of time AND has been written only once. SSDs usually calibrate changes in the statuses of cells over time via the flash management software algorithm. Due to the error in the software algorithm, the 840 EVO performed read-retry processes aggressively, resulting in a drop in overall read performance. This only occurs if the data was kept in its initial cell without changing, and there are no symptoms of reduced read performance if the data was subsequently migrated from those cells or overwritten. In other words, as the SSD is used more and more over time, the performance decrease disappears naturally. For those who want to solve the issue quickly, this software restores the read performance by rewriting the old data. The time taken to complete the procedure depends on the amount of data stored.

This partially confirms my initial theory in that the slow down was related to cell voltage drift over time. Here's what that looks like:

As you can see above, cell voltages will shift to the left over time. The above example is for MLC. TLC in the EVO will have not 4 but 8 divisions, meaning even smaller voltage shifts might cause the apparent flipping of bits when a read is attempted. An important point here is that all flash does this - the key is to correct for it, and that correction is what was not happening with the EVO. The correction is quite simple really. If the controller sees errors during reading, it follows a procedure that in part adapts to and adjusts for cell drift by adjusting the voltage thresholds for how the bits are interpreted. With the thresholds adapted properly, the SSD can then read at full speed and without the need for error correction. This process was broken in the EVO, and that adaptation was not taking place, forcing the controller to perform error correction on *all* data once those voltages had drifted near their default thresholds. This slowed the read speed tremendously. Below is a worst case example:

We are happy to say that there is a fix, and while it won't be public until some time tomorrownow, we have been green lighted by Samsung to publish our findings.

Samsung Electronics, a member of the WiGig Alliance, has just announced an implementation that is capable of achieving 4.6 gigabit (575MB/s) speeds under the 802.11ad standard. Samsung claims that they have overcome "the barriers to commercialization" of wireless over 60GHz. This band has several disadvantages, including resonance with oxygen molecules (included under the blanket of "path loss" in the press release) and its opacity to many solid objects (referred to as "weak penetration properties" in the release).

Some features that Samsung credits themselves with are beam-forming with less than four-tenths of a millisecond latency and the ability to track multiple devices simultaneously. Beam-forming in particular is said to help offset the mostly line-of-sight properties of earlier 60GHz prototypes. This allows the signal to be directed toward devices, typically by manipulating interference patterns to reduce the energy lost by transmitting to locations without a receiver and thus giving more energy to the locations that do.

Its usage as a product will mostly depend on how tolerant they are to non line-of-sight situations. This rate is comparable to a high-end SATA SSD. Samsung claims that it will be useful for their Smart Home and Internet of Things initiatives, similar to the Stanford and Berkeley announcement last month, but also mention it in terms of medical devices.

Samsung's new SM1715 NVMe PCIe SSD will use their new 3D V-NAND and come in a 3.2TB card, double the previous model and perhaps the smallest of the new line of SSDs they are working on. The stats are fairly impressive at 750,000/130,000 random read/write IOPS or 3GB/sec read bandwidth and 2.2GB/sec write bandwidth if you prefer that measurement. Samsung offers a nice mix of bandwidth and size with the new model and you can expect the competition to start releasing new models with increased capacities and speeds in the near future. The Register was not provided the full set of specifications for the drive but those should be forthcoming in the near future.

"Faster, fatter flash cards that speed up server applications are in demand, and Samsung has announced it is mass-producing a 3.2TB NVMe PCIe SSD using its 3D V-NAND technology. It says higher capacities are coming."

This does not apply to our North American readers, although it is good for them to know. To our European fans: Samsung has pulled out of the laptop market, for devices running either Windows or ChromeOS, in your region. The company is not commenting on how many jobs will be lost as a result of this decision. Samsung is not halting operations in any other region and this decision "is not necessarily reflective of conditions in other markets".

Parallels are drawn with Sony and its VAIO division, but this is significantly different. Sony sold its PC business to Japanese Industrial Partners who, in July, relaunched the brand in Japan. Samsung has not sold any division although there is rumors of upcoming restructuring. While Samsung will retain their brand and continue to develop products for the other regions, pulling away is always concerning for customers. It really could be a geographic anomaly, like Xbox was in Japan, or it could be a warning tremor. We simply do not know.

The International Data Corporation's latest Worldwide Quarterly PC Monitor Tracker shows that there were a mere 32.5 million touchscreen monitors shipped in Q2 2014, which accounts for 0.4% of the discrete monitors sold. This may have been a direct influence on the pitiful market penetration of Win 8 in SMB and Enterprise, as the much touted touchscreen support was meaningless to their users interaction with computers. The mobile side is a bit better but not much; DisplaySearch pegs the percentage of laptops with a touchscreen sold in 2013 was about 11% with a predicted 40% share by 2017 which still falls short of representing half of the market. You can pop by The Register for a link to some of the findings.

"Market monitor IDC's latest word on monitors goes some way to explaining limp enthusiasm for Windows 8: people just aren't buying touch-screen monitors.

Windows 8's user interface was designed to work on mouse-driven and poke-enabled devices. It's racked up plenty of sales, but not much love."

Many drives have died over the last year and a bit. The Tech Report has been torturing SSDs with writes until they drop. Before a full petabyte of data was written, three of the six drives kicked the bucket. They are now at 1500TB of total writes and one of the three survivors, the 240GB Corsair Neutron GTX, dropped out. This was a bit surprising as it was reporting fairly high health when it entered "the petabyte club" aside from a dip in read speeds.

The two remaining drives are the Samsung 840 Pro (256GB) and Kingston HyperX 3K (240GB).

Between those two, the Samsung 840 Pro is given the nod as the Kingston drive lived through uncorrectable errors; meanwhile, the Samsung has yet to report any true errors (only reallocations). Since the test considers a failure to be a whole drive failure, though, the lashings will persist until the final drive gives out (or until Scott Wasson gives up in a glorious sledgehammer apocalypse -- could you imagine if one of them lasted a decade? :3).

Of course, with just one unit from each model, it is difficult to faithfully compare brands with this marathon. While each lasted a ridiculously long time, the worst of the bunch putting up with a whole 2800 full-drive writes, it would not be fair to determine an average lifespan for a given model with one data point each. It is good to suggest that your SSD probably did not die from a defrag run -- but it is still a complete waste of your time and you should never do it.